A 6-year study on the pattern of periodontal disease progression.

The present longitudinal radiographic investigation was designed to study the change in the alveolar bone height over 6 years in relation to tooth type, age and the presence of previous bone loss in a group of 142 subjects (age 18-67 years) who were not under systematic periodontal treatment. The subjects were examined radiographically at baseline, and after 2 and 6 years, and sites showing significant (greater than or equal to 1 mm) change in the alveolar bone height during 2 consecutive examinations were identified. 90.2% of all examined sites showed no bone loss during the 6 years, while 8.6% and 1.2% of the sites exhibited bone loss during one or both examination periods, respectively. 3 groups of subjects within the studied population were identified. Approximately 5% of the subjects had high rates of periodontal disease progression whilst approximately 70% demonstrated very few or no sites with bone loss, and approximately 25% had a moderate level of disease progression during the study period. The results also showed that the number of sites exhibiting alveolar bone loss during the study period varied with respect to tooth type, age of the patient and presence of bone loss at baseline. In addition, significantly different rates of bone loss were disclosed with relation to tooth type (P less than 0.01), age (P less than 0.0001) and initial bone loss (P less than 0.01). It was concluded that periodontal disease progression occurs infrequently and may take the form of discrete or recurrent episodes of loss of periodontal support which can be influenced by the location of the site, age of the subject and previous periodontal disease experience.